__________________
Rick: Oh Cliff / Sometimes it must be difficult not to feel as if / You really are a cliff / when fascists keep trying to push you over it! / Are they the lemmings / Or are you, Cliff? / Or are you Cliff?

yes, the American FTC trade regulations of 1974, it requires preconditioning of 1 hour at 1/3 power and full power testing for 5 minutes....using a dummy load, signal generator and scope/distortion meter.....

__________________
the best advertisement for a good audio design is the number of diy'ers wanting to build it after all the years....never the say so of so called gurus....

I haven't put my amp into 'full-time' service yet, but I realize there may be heat issues if run for extended periods without additional cooling measures. Luckily I have vents in the top of my enclosure, but that may not be enough to dissipate the heat over the long haul. I may have to add a fan to HS.

yes, the American FTC trade regulations of 1974, it requires preconditioning of 1 hour at 1/3 power and full power testing for 5 minutes....using a dummy load, signal generator and scope/distortion meter.....

I haven't put my amp into 'full-time' service yet, but I realize there may be heat issues if run for extended periods without additional cooling measures. Luckily I have vents in the top of my enclosure, but that may not be enough to dissipate the heat over the long haul. I may have to add a fan to HS.

I'm pretty sure the amps they're supposed to run cooler than have vents in the bottom.

Any reason you can't drill some strategically placed holes?

Yeah, drilling holes won't be a problem if I go that route. I'd like to run in the amp more and take some temp measurements to see where it tops out under my typical operating conditions.

I have another class D amp that's based on the popular LJM design configured as two little monoblocks. With initial testing they run hot as well with the case top off. That case is smaller, but only has vents on the top too. However, the attached heatsink's fins on the LJM boards are running vertically, so the heat should dissipate easier and help keep them cool..er. Unfortunately, that case is too small for even the tiniest of fans. Again, no long run-in on that amp yet either, so I don't want to jump to any premature conclusions yet.

This thread comes at a good time for me because I am about to build an amp or two based on this to replace the old transistor amps from the 70's that I drag to (local community) theatres when I do sound design they don't have enough powered channels.

If you want to find more on what this amp will do and how it will behave, the IRC publication on the reference design is very detailed. Google "IRAUDAMP7D" and you'll find it on the International Rectifier website somewhere. The Parts-Express web page on this amp (which is the Sure board) says explicitly that it is based on the IRC reference design, but a quick look at the photos posted here lead me to believe that Sure simplified it somewhat. I would be very interested to compare the schematic from the Sure board with the reference design.

Some of the points made about this design in the IRC paper is that it is most efficient at high power levels, it has short circuit protection and thermal protection -- if the temperature sensed is >100C, the PWM shuts down. Useful features all, but I don't know if they require a couple of extra components to implement that the Sure people left out to make their price point. There are also very gory details about performance at various power supply voltages and load impedances. Very interesting reading.